Recent Workers Research Articles

A Revision of the North American Necydalini (Coleoptera, Cerambycidae)

The tribe Necydalini comprises those longicorn genera which have very short elytra exposing the abdomen and flat, unfolded wings with three veins in the post-cubital region. The group has been accorded various systematic positions within the family Cerambycidae, the most frequent of which have been either in the Lepturine or Molorchine series. LeConte (1850, 1863) advocated the former arrangement, recent workers have mostly followed the latter. Actually, although the resemblance between the Necydalini and the Molorchini is striking, it is highly superficial. The characters of the larvae, the venation of the wings, and the structure of the adult mouth parts all suggest a relationship to the Lepturinae (and Aseminae) and the tribe is here considered as belonging to that subfamily.

THE GENUS EPHORON

Williamson (1802) described the white fly Ephoron leukon. From his description of the insect and its habits, recent workers have been able to identify the species correctly. Hagen (1863) suggested that Baetis alba Say is a synonym of E. leukon Williamson. Eaton (1871, p. 124) was undecided as to the identity of E. leukon. In 1883 (p. 47), however, he indicated that leukon is a synonym of albus Say, which he considered to be a member of the genus Polymitarcys. This genus he had erected in 1868, employing Ephemera virgo Oliver as the genotype.

Nitrogen Fixation in the Rice-Field Soils of Bengal

IT has been proved by several workers by means of pure culture experiments that fixation of atmospheric nitrogen may take place by the activity of some algae, specially members of the group Myxophyceae. On the mucous sheath of most of these algae bacteria are generally present quite abundantly. Many of these are found to be Azotobacter, Clostridium and other nitrogen-fixing bacteria which are ordinarily distributed in the soil. Pure culture technique has been employed by recent workers to find out whether the bacteria and the various algae by themselves independently or jointly (symbiotic-ally) carry on nitrogen-fixation work.

Maternal Age, Order of Birth and Developmental Abnormalities

Since early times interest has centred round the problem of whether special virtue or taint is attached to the first-born child. Some recent workers, like Pearson (1914), have believed the first-born child to be liable to physical and mental handicaps. Still (1927) focuses attention on certain diseases which appeared to be more frequently manifested in the first child in a family than in children born later in that family. He also realized that maternal age might be a significant factor in other conditions. A summary of a good deal of the work done on these problems was published by Thurstone and Jenkins (1931). These writers drew attention also to parallel studies in animal genetics. Wright (1926 and 1936), by his analysis of Polydactyly and coat colour in guinea-pigs, laid a foundation for genetical work on maternal age. The effects he observed were due to alterations of characters in early offspring. Unfortunately, experimental animals rarely live long enough to make possible the corresponding study of maternal age effects at the end of the reproductive period. Evidence that birth order of itself is of significance in animal genetics has been scanty. Recently, however, Goetsch (1937) reported that the first eggs of the queen ant (Pheidole pallidula) give rise to small and physically feeble workers. In the present communication the results of some of the writer's recent researches on the effects of maternal age and birth order in human genetics are discussed. A multitude of human malformations are relevant to this study. Investigations of their respective ætiologies is of interest from the point of view of elucidating the effects of natural selection in man as well as from the standpoint of preventive medicine.

Nomenclature of Nudibranchiate Mollusca

WANTON changes in the nomenclature of animals are so injurious to zoology by confusing its literature, and so heavily handicap the study of systematic problems, that I seek the publicity of NATURE for the exposure of a particularly flagrant case. This is the synonymic List of British Nudibranchiate Mollusca by Iredale and O'Donoghue1, the nomenclature of which was adopted in the last edition of the “Plymouth Marine Fauna” of the Marine Biological Association (1931). My attention was directed to it by noticing that some extraordinary names for these animals were being used by recent workers at Plymouth, who naturally followed the guidance of the Association's official “Fauna”.

The Experimental Stream, A Method for Study of Trout Planting Problems

W ITHIN recent years many workers have been attempting to learn what happens to trout after planting. The usual method used has been to mark fish before planting by removal of fins or by tagging. Subsequent returns to counting weirs, in the case of migratory species, have formed the basis of conclusions as to survival rates. Foerster's work (1936) on sockeye salmon of the Cultus Lake system in British Columbia was the first to demonstrate the efficiency of natural propagation compared with artificial propagation of an anadromous species of fish. As is well known, the chief method employed in this work was not marking of large numbers of fish from which later total survival was determined, but to permit runs of the adult salmon to spawn naturally in some years, and in other years to strip the fish, hatch the eggs after the usual hatchery procedure, and to plant the resultant young back into the system. His method gave a measure of the difference between artificial and natural reproduction. In streams containing so-called non-migratory, inland trout, the problem of survival leads to considerable difficulties because all adults obviously cannot be trapped at one suitable trap or weir in their parent stream. The usual method used in such waters has been to mark fish prior to planting. Later records based on anglers' catches of marked fish have been used to calculate survival rates. Much allied useful information on migration, growth rates, production per acre, condition and trends of the angling, etc., has also been produced by such experimental work. The planting of marked fish, coupled with records of anglers' catches, leaves much to be desired. The immediate objective-survival of any given plant of fish-may be obtained with fair accuracy provided records of anglers' catches are sufficiently complete, and provided they are taken over the average life span of the marked fish planted. However, the facts thus obtained will not necessarily tell why any given survival rate was obtained, an answer that seems better afforded by the experimental stream method. The gap between planting and the anglers' creel is where our greatest ignorance lies today. In the application to management problems, we have yet to evaluate the fundamental ecological elements causing losses of planted trout, be they predation, disease, temperature, food, or cannibalism. Complete records of anglers' catches on selected waters will tell the story of what a water is producing to anglers in terms of pounds or numbers of fish caught per unit of water area. But what any given water should produce on a basis of its normal biological productivity is what we should know to balance actual fish crops against potential crops in the management program. White (1930) reported on experimental planting of trout in streams of Ontario and Prince Edward Island. He records many practical and scientific problems that confront workers attempting to determine survival rates of

Disturbances of Glucose Tolerance and of the Acid-Base Equilibrium in Manic-Depressive Insanity

It has been recognized for many years that in certain cases of mental disorder there is a demonstrable disturbance of carbohydrate metabolism. Among early observations may be mentioned those of Raimann (1902), Schultz and Knauer (1909) and Laudenheimer (1898). These workers reported the presence of sugar in the urine of patients suffering from depressive and anxiety states, and noted that the glycosuria often varied with the severity of the mental disturbances and disappeared with them. They remarked, however, that the phenomenon was of little diagnostic importance, inasmuch as it could be found in depressive states associated with many different types of mental illness. Such observations were of value as an indication for further research, but until it was established that the glycosuria was not due to a derangement of the renal mechanism of sugar excretion, it could not be claimed that the findings indicated such a fundamental metabolic disturbance as is now known to exist. Although Santenoise and Tinel (1923) stated that the renal threshold varies according to the mental state of the patient, many more recent workers have shown that the increased sugar excretion is always associated with a greater or less degree of hyperglycæmia, and, although agreement on this point is not complete, the balance of evidence favours the belief that such hyperglycæmia is alimentary in origin, and not spontaneous. As the earliest workers appeared to recognize, the metabolic disturbance is found mainly in states of depression, which may be retarded or agitated, and in certain cases of schizophrenia, which, too, may be stuporose or restless. Some investigators are of the opinion that the same disturbance may be found in states of mania as well as or even to the exclusion of depressive states, but this is a view which is held only by a minority.

INGUINAL HERNIOPLASTY WITH FASCIA TRANSPLANT

Herniorrhaphy of any type has been found in all clinics to be an inadequate procedure for the treatment of some inguinal hernias. Recognition of this fact has led the most recent workers on this particular problem to seek some method that will effect a larger percentage of cures. Resulting methods in almost every instance comprise the use of fascia either as a suture material or for plication in the abdominal structures or in the form of a transplant. In a search for reasons for recurrent or postoperative inguinal hernia, it is well to recall some anatomic conditions of the inguinal region. An indirect inguinal hernia has its exit from the abdominal cavity through the internal ring—an opening in the transversalis fascia. A direct inguinal hernia protrudes through the floor of the canal or else bulges this structure. It then becomes the first covering of such a hernia. All inguinal hernias,

The Activation of Cholesterol by Radiation

It was recently reported by A. H. Roffo and A. E. Roffo (16) that cholesterol after irradiation with sunlight or ultra-violet light is capable of blackening a photographic plate placed at a short distance from it. This effect was attributed to an ultra-violet phosphorescence of which spectra were recorded. Cholesterol irradiated for 240 hours with ultra-violet light and subsequently exposed for 72 hours before the slit of a high aperture spectrograph was said to yield two characteristic lines at 3533 A and 3572 A respectively. In view of the remarkable character of this spectrum and the importance attached to the phenomenon by Roffo in relation to the production of skin cancer by ultra-violet light, experiments were undertaken to investigate further the nature of this “phosphorescence.” In the course of our investigations we found that a fairly large literature already existed on the subject, a number of the phenomena subsequently observed by us having been established by previous workers. A general review of the subject was therefore thought of interest as in many cases recent workers appear to have overlooked earlier experiments.1 Photographic Blackening It has previously been observed by Střiteský (22), Hamano (5), and Hugounenq (10, 11), in addition to Roffo, that cholesterol after irradiation with ultra-violet light is capable of blackening a photographic plate in its vicinity. Hamano (6) and Střiteský (22) obtained the corresponding effect with X rays. We have verified the phenomenon with different types of exciting radiation, as follows:

Light as an ecological factor and its measurement

Refinement in knowledge and new scientific discoveries follow closely behind the introduction of new scientific instruments and new scientific techniques. And in no phase of botany has this been more evident than in the general field of plants in relation to light. Of outstanding importance has been the general availability of cheap reliable light-measuring devices that use as their sensitive element the photoelectric cell. Equally important have been the advances made in growing plants in controlled environment through the use of newly developed artificial sources of light, particularly the neon and sodium vapor lamps and the filters that transmit definite ranges of wave lengths. As a result recent workers have been able to surpass their predecessors in the accuracy of light measurement and in the precision of light control. And through advances in experimental design and statistical analysis developed by Professor R. A. Fisher and his American disciples (55, 156) they have learned how to analyze the separate and combined effects of varying several factors simultaneously in the same experiment. All three of these developments appeared before 1935 when the original paper under this title was published (148), but had not yet been put to widespread use in botanical research. Just as the trends in research might have been predicted ten years ago on the basis of new light sources, new light measurement devices and new experimental design and analyses, so today we may predict that advances in understanding the relationship of light to plants during the coming ten years will result from a more widespread use of fluorescent light sources and the introduction of heavy carbon as an indicator element in photosynthesis. We may expect further refinement of the mathematical relationships between total available light and plant growth as a result of the increased general availability of light recorders.

On Some Aspects of Digestion in Ciliary Feeding Animals

This paper embodies various observations which were made from time to time while the author was a member of the staff of the Plymouth Laboratory. It also outlines certain generalisations based on the author’s previous published work and that of other recent workers in the field of comparative physiology of feeding and digestion.

Colony Differences in Survival of Adrenalectomized Rats

There has been much disagreement among investigators concerning the life-span of the rat after adrenalectomy. While the majority of workers prior to 1930 found that 50% or more of their rats survived adrenalectomy, due to the presence of accessory cortical adrenal bodies, several more recent workers- have reported that all or nearly all of their animals died after adrenal removal. Gaunt offered evidence indicating that these inconsistent results may have been in part due to inherent colony differences in the susceptibility to adrenal removal. This report offers further evidence for such colony differences. Dr. J. T. Lewis of the Instituto de Fisiologia, Buenos Aires, one of the investigators to find high percentages of survival after adrenalectomy, sent a group of his rats to Dr. W. W. Swingle of Princeton University in the care of Dr. De Meio. He requested that they be adrenalectomized and their survival compared to colonies we had previously studied. Professor Swingle sent these animals to us to conduct this study. To eliminate variable factors due to care, diet, climate, etc., none of the original animals obtained from Dr. Lewis' colony were used in these experiments, but only the offspring, born and raised in our laboratory, in the same room with our animals. Operative technique and care were as previously described. Considerable of the adrenal pedicle and adjacent fat were removed, although this precaution does not apparently influence our survival results.

Diastase in Milk

Bechamp in 1883 was the first to recognize the presence of diastase in human milk; at the same time in cow's milk he found no trace of this enzyme.1 Bouchut2 and Moro3,4,5 confirmed the findings of Bechamp.During the last decade a number of investigators have attempted to establish a quantitative diastase test as a means of detecting whether or not a milk had been pasteurized. Namely, diastase would be entirely or partly inactivated during pasteurization, the extent of its destruction depending on the temperature and the duration of heating. The methods used by these workers, while claiming to yield quantitative results, are quite crude in comparison to the qualitative methods of Bechamp and Bouchut. The more recent workers find diastase in the milk of practically all the mammals6 examined and are able to determine diastatic activity in the presence of lead7,8,9 and even mercury salts.10 The latter fact is characteristic of the unreliability of these methods.We approached the problem with analytical proce...

Occurrence of Non-Motile Leucocytes

Sabin, Cunningham, Doan and Kindwall1 observed that when supravital counts were made on blood drawn every 15 minutes there appeared “showers of non-motile cells” at approximately hourly intervals. They interpreted these as being due to degenerating polymorphs which were actually dying in the blood stream. Beard and Beard2 confirmed the existence of these showers, and were able to increase their magnitude without altering their rhythm by the injection of sodium citrate. More recent workers (Smith and McDowell,3 Jones, Stephens, Todd, and Lawrence4) have been unable to confirm these observations, and find that the non-motile cells occur at irregular intervals and are probably artefacts.If the non-motile cells are really dying polymorphs, most of them should be old cells, as determined by the criterion of the number of lobes in the nucleus (Cooke and Ponder5), whereas if they are artefacts, we might well expect both young and old cells to be affected, i. e., cells of all the classes of the polynuclear count....

VIOSTEROL OF HIGH POTENCY IN SEASONAL HAY FEVER AND RELATED CONDITIONS

Until recently, the literature on the blood calcium and the therapeutic value of calcium in allergic conditions has been replete with contradictions. It is unnecessary in this work to do more than summarize various views. Briefly, there are those who believe that a calcium deficiency is present in allergy, and that calcium is indicated as an adjunct in treatment, and those who find no such deficiency and deny the value of calcium as a therapeutic agent in allergic conditions. Almost all the work since 1928 based on blood chemistry studies made since the development of the Kramer-Tisdall technic for calcium determination supports the latter point of view. Among the more recent workers who also review the literature to date are Cohen and Rudolph1and Ramirez.2In studies on a large number of various types of allergic conditions these workers found no calcium deficiency and no improvement or only

MODE OF PRODUCTION OF THE FIRST HEART SOUND

The experimental observations on dogs' heart sounds here described were intended to cast further light on the relative importance of muscular and of valvular elements in the production of the first heart sound. The theory based on these observations seemed to conflict with the views of recent workers, particularly with those of Wolferth and Margolies in their excellent study of the variations of intensity of the first sound in heart block. The relation between auricular systole and the first sound is therefore described in some detail. It is believed that the theory offered gives a coherent explanation of all the phenomena noted in the study of the first heart sound. 1 METHODS Dogs anesthetized with a brand of chlorbutanol were subjected to midline thoracotomy, and respiration was artificially maintained. The heart sounds were recorded by a collodion Frank capsule from small tambours attached to the ventricular surface by short rigid

THE NYMPH OF CINYGMA INTEGRUM AND DESCRIPTION OF A NEW HEPTAGENINE GENUS

The species, integrum Eaton, described from material collected in Washington and Oregon states, was designated by Eaton as the genotype of Cinygma. I have already (1926, Can. Ent. LVIII, 302) recorded the capture of adults of this species in the Coast range of British Columbia and at the time expressed some doubt as to whether all the species at present included in this genus were strictly congeneric. Since nymphal structures have been recognized by a number of recent workers as of great importance in furnishing distinguishing characters in the Heptagenine genera it was with considerable interest that I discovered among material collected in the Hope Mts., B. C. in 1932 by my assistant, Mr. A. N. Gartrell, a bred female adult of integrum, together with its nymphal exuvia, preserved in alcohol. A study of this exuvia soon convinced me that in the nymphal gills and mouth-parts there are excellent and in part unique structural details which should at once establish not only the validity of the genus but also its limitations and position in the group of allied genera.

LEUKOCYTIC RESPONSE TO MEASLES

The precise nature of the leukocytic reactions during measles still remains a subject concerning which there are surprising differences of opinion. Although it is generally held that a leukocytosis is present during the incubation period, followed as a rule by a leukopenia during the acute febrile stage,¹there is a lack of agreement regarding the changes in the differential count. It was early pointed out by several investigators²that the fall in the blood count was due chiefly to a diminution in the number of lymphocytes. Diametrically opposed to this finding, however, have been the reports of a lymphocytosis occurring simultaneously with the rash.³Moreover, it has been maintained⁴that variations in the number of polymorphonuclear cells principally account for the leukocytosis or the leukopenia observed in the different phases of the disease. More recent workers,⁵on the other hand, have laid great stress on

The origin of erythrocytes in herring ( Clupea harengus )

The origin of erythrocytes in fishes presents an almost unique problem on account of the different methods of their formation and the varying stages of development at which they are found in the circulation. The general opinion would seem to indicate that all blood cells arise from mesenchymal type of cells arise from mesenchymal type of cells at at very early period in the embryonic development. For a precise comprehension of the development of the blood and vascular system it is only necessary to consider the opinions of some of the recent workers on the subject. According to Swaen and Brachet (1901) the mesoblast in the posterior half of the embryo consists of an inner primary somite portion of the primary lateral plate part a adjacent to the somites divides off and forms a mass of intermediate cells. The primary lateral plate grows towards the median line pushing its way beneath the somites to form a keel-shaped mass which cuts off the somites from the peritonial cavity. This keel-shaped mass of cells unites with similar cells from the opposite side, resulting in a large median group of intermediate cells. This same process takes place in the posterior region so that the intermediate cell mass becomes a continuous layer. From this definite region of the mesoblast called the intermediate cell mass originates the heart, vasular system, and the blood in the embryo. Though the mesodermal origin of the vascular system and the blood cells is generally accepted, the exact process of the formation and development of the different kinds of blood cells is a highly disputed problem. Some of the earlier workers have maintained that all the different kinds of blood cells originate from the same types of mesenchymal cells. According to this view, the mesenchymal cells change into stem inother cells which, on the one hand, give rise to leucocytes and on the other, to typical erythrocytes. This point could not be verified by any study of normal material, as circulation of the embryonic fluid is established very early before the appearance of blood corpuscles, so that when the latter are formed, they are swept into the circulating current and carried to all parts of the body. This necessarily makes the study of the origin of blood cells a rather difficult problem.

EXPERIMENTAL SHOCK

A great deal of confusion has arisen from the use of the term shock. Conditions that are probably little related to one another are classified together under this general heading. Several recent workers have suggested other terms in an endeavor to lessen the misunderstanding. Until the factors that are responsible for the decline in the volume of circulating blood and the drop in the blood pressure are better understood, it would probably be advisable to designate the initiating agent as, for example, shock following trauma to an extremity, shock following burns, or shock following injury to the central nervous system. Shock resulting from injury may be roughly divided into two types: (1) primary shock, in which a low blood pressure follows immediately, and (2) secondary shock, in which at least an hour usually elapses between the time of injury and the development of a low blood pressure. It is the